Refrigerating apparatus



Nov, 11, 1924. v1,515,165

E. P. OSWALD REFRIGERATING APPARATUS Filed Aug. 21, 1920 Patentv NW. TIES r. OSWALD, or DETROIT, MICHIGAN, AssIeNoIanY mnsNE ASSIGNMENTS, To THE HOOVER COMPANY, `or NORTH CANTON, OHIO, .a CORPORATION or OHIO.

REFRIGERATING APPARATUS.

Appaicauon mea August ai, 1920. serial No. 405,009. I

To eiZZ whom t may Gon-cem:

Be it known that I, EARL P. OswALma citizen of the United States, residing at De troit, county of Wayne, State of Michigan,

have invented a certain new and useful Improvement in Refrigerating Apparatus, and declare the'following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it f pertains to make and use the same, reference eing had to the accompanying drawings, which form apart of this specification.

This invention relates more particularly to cooling coils for refrigerating systems, the principal object of which is to provide a cooling coil having what is known as a sharp freezing chamber in conjunction therewith in which the temperature 'is maintained practically at the predetermined point irrespective of variations in temperature in the storage compartment within which the coil is positioned. A further feature of the invention is involved in the construction of a coil wherein a portion thereof is exposed to the atmosphere of the compartment to be cooled and a portion `of which is insulated from the atmosphere of the compartment. In artificial refrigerating systems heretofore known operating to hold the storage compartment at a temperature of about fortyfive degrees F., a cooling coil is utilized in the storage compartment and in vclose proximity to the coil is provided a tray of some character having depressions or compartments for the freezing of water therein to provide ice for household use. Such devices as heretofore known are only partially successful in operation due tO variations in temperature of the storage compartment, especially in such systems where the operation depends upon the temperature of the compartment. When the4 temperature has increased to a certain predetermined degree the motor is energized and the refrigerant medium is compressed and then expanded in the cooling coil and the absorption of the4 heat in the storage compartment and upon reduction of the temperature thereof to a predetermined degree causes cessation of Operation of the system and as the storage compartment again becomes warmed the process is repeated. 'With such an apparatus as previously known the ice in the trays adjacent the cooling coil becomes melted previous tothe succeeding opera-tion of the system. The apparatus herein disclosed is designed to prevent this subjection of the' partial melting of the ice. With these and other objects in view, I have provided a portion of the cooling coil so shielded from atmosphere o'f the storage com artment as to.

be practically wholly una ected thereby during the periods of idleness of the refrigerating system vand another portion thereof depended upon to cool the storage compart. ment thereby providing a definite part of the cooling coil -for the performance of the specific functionof freezing water and hold' ing the same in frozen condition without variation in its character. These and other objects and novel features of the invention are hereinafter more fully described and claimed, and the preferred form of construction of apparatus embodying my invention is shown in the accompanying drawings in which- Fig. 1 is a front elevation of a refrigerator showingA the general relationship of the cooling coil'and storage compartments.

Fig. 2 is a vertical section of the cooling coil indicating the construction thereof and in connection with which is diagrammatically shownl the remaining parts of an articial refrigerating system.

Fig. 3 is adetail in section showing the valve for the vacuum space of the coil body.

j It is to be understood that this refrigerating system may be of any approved type either a brine circulatingsystem or a system in which sulphur dioxide or other gas is used as a refrigerant medium. The system diagrammaticallyshown is of the latter type, and the motor, pump and compression coil may be located in any approved manner relative to the storage compartment either at the -top or even remote therefrom as in some systems now in use. In any eventthe cooling coil 1 should be located in such manner y that the atmosphere of the storage compartment is affected thereby preferably by placing the same within the compartment proper as is herein shown.' It may, however, be placed in a separate compartment open to construction Uli the stora e compartment in such manner that the a1r of the compartment may circulate through or about the cooling coil.

lln my preferred form of construction the cooling coil 1 is placed in the upper part of the storage compartment on one side thereof, which compartment is preferably divided into two parts by the dividing wall 2 having an opening 3 and 4 at the top and bottom respectively so that air may pass downward in the com artment 5 in which the coil is located and) upward in the compartment 6 through the aperture 3 to and in contact with the cooling coil where the air is cooled and again pass downward in its circuit. lln the diagram shown in Fig. 2, the pump and motor is indicated at 7, the discharge line of the pump connects with the compression coils'8 where the refrigerant is cooled from which it passes through the usual expansion valve 9 to the cooling coil 1, and from thence by means of the pipe 10 to the intake side of the pump. The pump thus tends to maintain a minus pressure in the cooling coil and expansion side of the system. lin the apparatus illustrateda gas is utilized as a refrlgerant, as for instance SO2, and the pressure maintained on the coils 8 will cause iquefaction of the same as soon as the temperature thereof is at normal atmospheric temperature. rllhe liquid on passing through the expansion valve 9 tothe expansion side of the system where the pressure is relieved expands or boils and tends to absorb heat from the surrounding atmosphere of the' storage compartment and when the temperature-of the coil is sufficiently reduced the re frigerant tends to liquefy in the ex ansion coil, especially during the period of ldleness of the system and advantage is taken of this liquefaction in the expansion coils by the hereinafter described.

ln order that the cooling coil may be pron vided with a portion thereof to practically so function as to maintain a certain temperature in the sharp freezing chamber and a portion thereof utilized to maintain the desired higher degree of temperature of the storage compartment ll construct the cooling coil as follows-ll provide a receptacle like member'.v 1l one end of which is open and provided with an external flange 12. Within the receptacle ll place a similar member 13 having an external Hange 14. On this inner member 13 ll form a coil 15, the turns of which are practically in contact with the outer surface of the member 13, the first or end turn of which is provided with a projection 16 extending through an aperture in the outer member 11. At the opposite end ll provide a similar outwardly extending end 17 of the coil to which is connected the outer coil 18 formed of a series of turns on the outside of the member 11. These turnsof the coil 18 may be slightly 'greater in'inner with a Lerares diameter than the diameter of the member 11 and thus slightly spaced therefrom to allow a comparatively free circulation of air through and about the exterior of the coils. The member 16 of the inner coil is connected with the pipe line 19 leading from the expansion chamber 9 and the end of the coil 18 is connected by means of the pipe line 10 with the intake side of the pump 7. By this arrangement the two coils are in series and fluid passes from the expansion valve first through the inner coil 15 and then through the outer coil 18 to the compressor.

With the ordinary household refrigerator of about eight or ten cubic feet l use copper tubing of about one-half inch diameter. 'llhe outer coil is about ten inches in diameter and iifteen inches in length and there is a space of about one inch between the walls of the outer and inner receptacles 11 and 13. Preferably, the space between the receptacles is practically exhausted of air and for this purpose thetwoflanges 12 and l14 have soldered `thereto a ring member 21 closing the opening between the two rece tacles. Also the a ertures through which t e portion 16 and 1 of the inner coil project are provided plate 22 and 23 respectively which is soldere in position and the tubes soldered in the respective plates. At a convenient point l provide a valved conduit 24 similar to the valve stem .of an inner tube of anautobile tire, the valve being position@ to close on'outward pressure and to open on presu sure from the interior. When the space between the members 11 and 13 has been sealed, ll attach a pump to this member 2li and withdraw all the air possible whereupon, the valve being closed, the receptacle is sufliciently effectively sealed for all practical purposes. Subsequent to the removal of the pump the chamber 25 formed by the interior receptacle is provided with a cover member of any approved type shown at 26 whichv is preferably hollow in form from the interior of which the air has been exhausted and thus providing an eicient insulating member for closing the receptacle 25 to the atmosphere of `the storage compartment.

As shown in lFig. 1 this cooling coil ,is posil be placed. Due to the low 'temperature maintained within the sharp freezing chamber this water is soon frozeru 'llhe pur ose of this peculiar construction of the coding coil` is to provide a portion thereof which is unadected by variation in temperature of llll -freezing chamber.

'forty to fifty degrees F., which is a sulficiently high temperature to cause melting of ice if exposed to the atmosphere of the compartment as has heretofore been the case. By insulating a portion of the vcooling coil and provlding a sharp freezing chamber the atmosphere of which is affected by this insulated portion alone of the coolin coil, I secure a decidedly beneficial resu t in that the sharp freezing chamber 25 will remain for 'a considerable period of time below a freezing temperature and without any material change therein. Withl these systems as utilized for household use the period of operation of the compressor is from about fifteen minutes to one half hour and theperiod of non-operation is for from about one hour to one and one half or two hours. It is therefore evident that the construction as outlined is suiiicient to hold the temperature of the sharp freezing chamber practically without change as the period of inactivity of the refrigerating s stem is for not more than a two hour perio under n ormal conditions.

It is therefore to be seen that I have taken advantage of the principle involved in the well known vacuum bottle in common use for maintaining liquids at a certain temperature. rIhe vacuum prevents the heat of the storage compartment from affecting the temperature of the interior of the sharp The construction, however, is superior to the vacuum bottle type of construction in that a cold medium is introduced in the vacuum space by which the temperature of the sharp freezing chamber is controlled and maintamed. The vacuum space shields the chamber as statedand also shields a portion of the expansion coil which contains the refrigerant Afiuid and provides a portion of the coil in which liquefaction may take place (due to its temperature) when the apparatus is idle. When the apparatus is idle the Huid in the portions of the expansion system exposed to atmosphere of the com artment may take up heat and become gasi ed causing a pres-v sure in the expansion coil'which assists in the liquefaction of fluid. in the colder portion of the coll.l By' the construction outlined in which a p ortion of the coil is insulated from infiuence of the atmosphere of the storage compartment and in which liqnefactonl may take place as stated, I secure the further advantage that, upon the starting of operation of the compressor after a period of inactivity, the compressor very soon begins to first cause the liquid to boil taking up the heat of the storage compartment almost immediately and sooner than would be thecase if ,the liquid had first to be transferred through the expansion valve. In fact soon after starting up the compressor begins to draw`refrigerant in liquid form from this coil and the work of the compressor is therefore reduced to a considerable degree.

As before stated this type of cooling coil may be utilized with varlous types of artiicial refrigerating apparatus. If a brine is to be circulated the benefits arising from liquefaction as stated when SO2 is used does not pertain but all the other objects of the invention, however, would bev obtained by this general construction of the cooling coil particularly in that aportion of the cooling coil is insulated from influence of the atmosphere of the storage compartment and,

positioned to affect the sharp freezing,

chamber only. I therefore do not desire to limit myself particularly to the character of the refrigerant utilized or to the general construction of the refrigerating system but to the cooling coil which may be of various shapes and sizes and ma vary considerably in detail of constructlon within the limitations of the appended claims.

l. A cooling coil for artificial refri erating systems comprising a double wa led receptacle providing a central insulated chamber, said central chamber having a closable opening, a coil about the outer surface of the receptacle, and a coil between the inner and outer walls of the receptacle in series with the outer coil.

2. A cooling coil for artificial refrigerating systems, comprising a double Walled re ceptacle providing an insulated central compartment, and a coil forming part of the circulation system` of the apparatus ositioned between the inner and outer wal sf of the receptacle. y

3. In an artificial refrigerating system including astorag'e compartment and a circulating system for the refrigerant, a double walled receptacle within the compartmentI providing an insulated central chamber, a cooling coil having a portion thereof about the exterior surface of the ,receptacle and a portion thereof between the inner and outer walls of the receptacle, the twoportions being in series and the refri erant fluid passing first to the interior co and then to the exterior coil.

llt

4e. A cooling coil for artiicial refrigeraning systems comprising the combination with the storage compartment of the refrigerator, of a cooling coil formed of two parts, one of said parts being exposed. to the atmosphere of the compartment, a yacuuxn chamber, the other of safiol parte bein positioned Within the vacuum charnlrer9V an a freezing chamberenclosed hy Irho Vacuum chamber, the freezing chamber being provided with a closalole opening. y 5. llnran artificial rerigcrating system including a Stora e compartment, compression and. ex answn lines and thermostatically contro led apparatus for circulahing the refrigerant, the combination therewith normes of a cooling coil rin the expansion line, said coil consisin of two parte in series, the first of the said parts beginnn with the inlet end of the expansion line' eng Wholly insulated or shielded 'hroughout the length thereof from influence of temperature yariations in the stornnfc compartiment, the said second part of he coil lying wholly exposed to influence of temperature change in thc storage compartment, and a chamber subject only to hhe inuencc of the insulated. portion of the cooling coil.

lin testimony whereof, ll sign this specification.

EARL r. osi/Vroon. 

